Diesel injection pump pressure test ?

I am would like to find out the approximate pressure of my Ford 7.3 IDI
F250 injection pump . I suspect in is going bad but I want to confirm
it before replacing it . Can I get a 0-3000 psi guage and plumb it up
( with the pessure appropriate fittings and metal line ) to one of the
the injector pump ports and crank it for a couple of seconds ( cold, no
glow plugs ) or would I be better off installing it in a Tee and
connect the injector ( basically running it parallel) . As I presume
that it takes about 1800 psi to run the injector , the pump should be
running a minimum 2,000 psi hot or cold . =thanks

> wrote in message
oups.com...
> I am would like to find out the approximate pressure of my Ford 7.3 IDI
> F250 injection pump . I suspect in is going bad but I want to confirm
> it before replacing it . Can I get a 0-3000 psi guage and plumb it up
> ( with the pessure appropriate fittings and metal line ) to one of the
> the injector pump ports and crank it for a couple of seconds ( cold, no
> glow plugs ) or would I be better off installing it in a Tee and
> connect the injector ( basically running it parallel) . As I presume
> that it takes about 1800 psi to run the injector , the pump should be
> running a minimum 2,000 psi hot or cold . =thanks
>

For a good test you need the injector out of the engine, this enables you to
determine if the spray pattern is OK or if any dripping is occurring. This
test is normally done with a hand operated pump.

Jack

"Jack Hayes" > wrote in message
...
>
> > wrote in message
> oups.com...
>> I am would like to find out the approximate pressure of my Ford 7.3 IDI
>> F250 injection pump . I suspect in is going bad but I want to confirm
>> it before replacing it . Can I get a 0-3000 psi guage and plumb it up
>> ( with the pessure appropriate fittings and metal line ) to one of the
>> the injector pump ports and crank it for a couple of seconds ( cold, no
>> glow plugs ) or would I be better off installing it in a Tee and
>> connect the injector ( basically running it parallel) . As I presume
>> that it takes about 1800 psi to run the injector , the pump should be
>> running a minimum 2,000 psi hot or cold . =thanks
>>
>
> For a good test you need the injector out of the engine, this enables you
> to
> determine if the spray pattern is OK or if any dripping is occurring. This
> test is normally done with a hand operated pump.
>
> Jack
>
That's for testing the injector, it sounds like he wants to test the pump
itself.

I want to test the pump pressure itself ( at least get a good idea as
to whether it is going bad ) not the injectors .

If you have a way in, a guage that reads the pressures desired & the
specs your already there. Most of the 7.3s I see have an extension of
some sort on top of one of the injectors (usually right front) that
screws onto the top of the injector, then the line screws onto that. If
you had one of these (from a junkyard) you could tap threads into the
side of it to accomodate your guage & it would be a bolt in/ removable
situation so you wouldn't have to destroy anything in the fuel system
to tap in.

In article .com>,
" > wrote:

>I am would like to find out the approximate pressure of my Ford 7.3 IDI
>F250 injection pump . I suspect in is going bad but I want to confirm
>it before replacing it . Can I get a 0-3000 psi guage and plumb it up
>( with the pessure appropriate fittings and metal line ) to one of the
>the injector pump ports and crank it for a couple of seconds ( cold, no
>glow plugs ) or would I be better off installing it in a Tee and
>connect the injector ( basically running it parallel) . As I presume
>that it takes about 1800 psi to run the injector , the pump should be
>running a minimum 2,000 psi hot or cold . =thanks

Injector pumps are positive-displacement things, so you absolutely
must have a way for the diesel to get out. If you stuck the gauge
directly to the end of the line you'd break something. Probably the
gauge, but no guarantees it won't ruin the pump.
You cannot tee-in to the fuel line either. Besides the lines being
too stiff for you to make room for the tee, the volume of that line is
calibrated. Changing it will throw off the pressure your fuel pump
develops when injecting, so your measurements will be meaningless.
If the pump cannot develop enough pressure to run the injectors due
to wear you'll have hell even starting the engine. But that shouldn't
ever happen unless it's been fed bad fuel.
Your pressure is controlled by the injector needle, not the pump--it
just builds pressure until that needle gives. Before pulling the pump
what you need to do is bench-test your injectors as another poster
described. Or test them in the engine:
If your problem is rough running from a single bad cylinder, then
with the engine running, crack each fuel line loose (one at a time) and
see if diesel fuel is spilling out to make sure that cylinder is getting
fuel. Crack it at the injector end, so you don't wind up letting an air
bubble into the fuel line. You may even let out an air bubble in there
already.
Also listen to the engine, if there is no change to the engine
sound/RPM when you crack it, or you start with a loud hammering sound
that goes away when you crack the line, you've isolated the bad
cylinder. Swap that injector with any other injector in that engine and
run the test again. If your problem moved when you moved the injector,
the injector is bad--replace or rebuild it. If the problem stayed in
that cylinder, then you either have a problem in the pump or you have a
mechanical problem, like a valve setting. Do the usual mechanical
checks on the engine. If the engine's good, it's the pump.
Once you narrow it down, you can decide what to do. Checking the
pump's performance any further requires some hideously expensive
equipment and is done off the engine. If you find a problem with the
pump you might as well pull it and take it to a pump shop for a rebuild.

--
B.B. --I am not a goat! thegoat4 at airmail dot net
http://web2.airmail.net/thegoat4/

The best way is to remove the pump and attach it to a test arrange to check
for all of fuel delivery aspects.

Regards,

Ralf
--
www.omnibusclub.de

I have workred in a fuel pump shop for 15 years
diesel pumps realy work on volume of fuel
depends on load and speed ,if your motor starts and runs / idle smooth
the pump is in pretty good mechanical condition
if it is hard to start hot or cold and the motor is in good condition
,compression , timing etc
the pump elements are worn out through dirty fuel
a simple test to check pump elements
remove an injector from motor and turn it up side down
replace it back on the injector pipe (dont worry about the return pipe let
it flow to the floor /container )
crank the motor over and watch the spray patten (in the run position )
KEEP HANDS AND BODY AWAY FROM DIESEL SPRAY ,
DIESEL IN YOUR BLOOD STREAM YOU DIE QUICKLY
the spray should be an atomise spray ( not like an oil can)
to check for a miss undo one injector pipe at a time if you find a miss swap
the injector to an other cylinder
and see if the miss follows the injector
the best thing to do is remove the pump and have it tested on a test bench
and reset to the test data
> wrote in message
oups.com...
>I want to test the pump pressure itself ( at least get a good idea as
> to whether it is going bad ) not the injectors .
>